How clean is our sea water?
Published 18/06/2015 | 02:30
This year, 86 of Ireland's beaches achieved Blue Flag status, which is based on compliance with 33 strict criteria, including environmental management, safety and security, and water quality. The main water quality testing is for two types of faecal bacteria, Escherichia Coli (also known as E. coli) and Intestinal Enterococci. Sea water samples are tested in the lab and, during Blue Flag season, there must be no more than 30 days between samples.
However, in addition to bacteria such as e-coli and streptococci, our seas and oceans face many other water quality issues, such as emerging contaminants like pharmaceuticals, heavy metals and, more recently, plastics.
Plastics have an enormously detrimental effect on our seas and oceans. Almost everything in our daily life is wrapped in plastic and, as a result, ocean plastic has turned up literally everywhere. It has been found in the deep sea and buried in Arctic ice. It has been ingested with dire consequences by some 700 species of marine wildlife; it is fatal for these creatures because it can obstruct the stomach or intestine, causing starvation and, ultimately, death.
Dolphins and whales are particularly susceptible, as they can often mistake floating plastic for food. Last year, a young female Sei whale, an endangered species, was found dead floating off Chesapeake Bay, USA after ingesting a piece of plastic from a DVD case.
There is an estimated 800m tonnes of fish in oceans worldwide, and 100m-150m tonnes of plastic, which is increasing every year. Unless we dramatically alter our behaviour, the amount of plastic in the ocean will soon surpass the amount of fish.
Plastic in the sea also affects human health. The chemicals that leach out from plastics come from lead, cadmium and mercury. These toxins have been found in many fish, which is very dangerous for humans. Other toxins are directly linked to cancers, birth defects, immune system problems, and childhood developmental issues.
Unless we radically change our current behaviour, the sea will house more plastic than fish, and more and more of our beaches will become unsafe for swimming and bathing.
We need to to raise awareness of the damage plastics and other littering can do to our sea . We need to get involved in local conservation groups that help clean our beaches.
We need to restrict our use of plastic and recycle the plastic we do use. We need to stop flushing dangerous items down the toilet, as these all end up in our sea. We need to think before we act. We need to recognise we are all part of the same ecosystem.
Professor Fiona Regan is Director of DCU Water Institute. Her research focuses on environmental monitoring of our waters.